Marker for printing on curved surfaces



C. H. DAVIS Aug. 29, 1967 MARKER FOR PRINTING ON CURVED SURFACES Filed Dec. 7, 1964 INVENTOR. CHA2L 5 Al. DAV/.5 BY M, M 2 Md 4;; Armemsy United States Patent Office Patented Aug. 29, 1967 3,338,162 MARKER FOR PRINTING N CURVED SURFACES Charles H. Davis, Monroeville, Pa., assignor to Jas. H.

Matthews & Co., Pittsburgh, Pa., a corporation of Pennsylvania Filed Dec. 7, 1964, Ser. No. 416,518 3 Claims. (Cl. 101-379) This invention is for a marking device for printing on non-planar surfaces, particularly spherical or substantially spherical surfaces which are either convex or concave.

The invention is particularly applicable to the application of a marking to 'either the exterior or interior of glass bulbs such as the glass blanks used in the manufacture of incandescent lamp bulbs, electron tubes and the like, but it is applicable to other spherical or generally spherical surfaces. By way of illustration and not as limiting the invention, it may herein be described in connection with marking glass envelopes as above mentioned.

In commercial practice, it is desirable to print a trademark and/ or other indicia on the end of glass bulbs, either inside or outside, with an ink that is subsequently fired in the process of degassing and finishing the lamp bulb or other article. A rubber marking die is used because it can press against the glass and m'eld without likelihood of breaking the glass. Such a die must have a generally fiat or planar surface so that when it is contacted with an inking roll, the faces of all of the characters, being in a plane, will be equally inked. Heretofore the printing element has had a cushion backing through which it is pressed against the glass, and by which it is mounted on an operating stem. However, when this die is then brought against the outside end of an electric lamp bulb, and pressed against it to make an impression on the bulb, the die first makes contact with the glass at one point. Then as the marking die is pressed down, there is a tendency for the marking characters at the center of the die to squash down and as pressure continues for the die to stretch, pulling the surrounding characters already contacting the glass away from the center. Both the squashing of the characters and the sliding tend to smear the ink, and produce printing that is not sharp in outline.

According to the present invention, the central area of the printing die is likewise made of rubber, but there is a cavity at the back of the central area and it is attached to the rod which moves it into printing contact with the glass only at or near its periphery in such manner that it can be forced into a concave, or convex, shape without the same stretching or squashing action, and therefore it prints much more sharply and evenly and without noticeable blurring.

The invention therefore has for its object to provide a marking die of improved construction for printing on spherically curved surfaces.

The invention may be more fully understood by reference to the accompanying drawings in which:

FIG. 1 is a side elevation of a marking die embodying the invention and operating stem on which it is mounted;

FIG. 2 is a vertical section through FIG. 1;

FIG 3 is an enlarged schematic view showing the deformation of the marking element during printing; and

FIG. 4 is a view similar to FIG. 1 with a smaller die.

Referring first to FIGS. 1 and 2, the numeral 2 designates the steel rod or stem which is commonly used in marking machines of the type used for this purpose for moving the die away from the marking position to an inking position and then to the printing position. Sometimes this rod is upright, as shown; in other machines it may be above the work piece and move down to engage the Work,

and it may be horizontally movable. As here shown, it has an annular rib 3 spaced from its die mounting end.

The die, designated generally as '4, has a cylindrical deformable elastic rubber body portion 5 in which is an axial opening 6 to fit snugly about the rod 2 and with an annular recess molded therein to receive the collar or rib 3.

At the top of the cylindrical body portion is a spherical notch 7 that undercuts the top disk portion 8 on which the printing characters 8a are formed in'relief. Inside the body there is a cavity 9 of larger diameter than the rod so that the disk portion 8 is supported on the body only by end face of the stem to an open port 12 below the body of the relatively thin annular cavity wall or neck 10. The marking disk portion extends at its periphery beyond this neck while the central area of the disk spans the cavity 9.

There is an air passage 11 extending axially from the the printing die. The rib 3 is so positioned that in operation the end of the stem 2 may never contact the inner face of the disk portion 8.,

A shown in FIGS. 1 and 2, the surface of the disk, ex-; cept for its type, which are of uniform height, and hence are also in a plane, is flat so that all of the type will be inked when the inking, roll commonly provided in these machines passes across the type surface.

In FIG. 3 the parts are inverted with respect to FIGS. 1 and 2. When the disk is pressed against the convex surface A to be marked, the center of the disk, being unsup ported, bow inwardly, tending to deflect the periphery toward the object A, somewhat in a cantilever fashion, with the compressive forces being transmitted through the neck and tending to slightly contact the diameter of the neck. This action, with the edges of the disk unsupported, gives a clean, sharp impression. Air in the cavity is vented through the passage 11 and port 12 to the atmosphere.

As the rod moves away from the piece A upon completion of the marking, the disk portion springs back to its normal flat form and air flows in the reverse direction to prevent any vacuum in the cavity that would tend to keep it from flattening out.

In printing on a concave surface, the peripheral edges of the disk first contact the work piece, creating a force tending to how the center out away from the end of the rod and into a convex contour, the neck connecting the disk and body, then flexing outwardly to a slight extent.

For very small marking devices, the structure shown in FIG. 4 is preferable. Here the mounting stem or rod is the same as in FIGS. 1 and 2, and corresponding reference numerals are applied thereto.

The body of the printing is generally similar to that shown in FIG. 1, being made of an elastic rubber or rubberous material, with a cylindrical main body portion 15 with an axial passage to fit on the stem 2, but the lower end of the body seats against the rib 3 of the stem instead of enveloping it, as in FIGS. 1 and 2. The passage for the stem extends upwardly above the end of the stem when the body is seated on the rib and thereby provides a cavity 16 under the flat disk portion 17 that carries the marking indicia 17'. The disk portion is attached to the body by a thinner annular wall portion or neck 18 of reduced diameter, providing the undercut peripheral notch 19.

The whole device shown in FIG. 4 is not only shorter, but of overall smaller diameter than the one shown in FIGS. 1 and 2 so that when it is used for marking the inside of a glass article, it can be entered through a neck or passage of smaller diameter. The flexing in printing, however, occurs on the same fashion; the breathing, i.e., the expulsion and intaking of air, is the same, and the two forms may be interchangeably usable on the same machine.

The provision with this die of a stem with an annular rib 3 spaced from the die-c-arrying endis important for preventing endwise movement of the die body on the rod under pressure of printing to keep the end face of the rod spaced below the type-carrying disk a s'ufficient distance to prevent the inner face of the disk from contacting the end of the stem, as otherwise the cavity inside the printing element would be ineffective. It will be understood that the terms spherical or generally sphericallycurved convex surfaces as used herein include rounded surfaces such as in rods, flourescent bulbs and the like.

While I have shown and described certain preferred embodiments of my invention, various changes and modifications may be made in the construction within the contemplation of my invention and under the scope of the following claims.

I claim:

1. In a device for printing on spherically-curved convex and concave surfaces, an operating stem comprising a rod having an end portion to receive a marking die, a marking die having a cylindrical body with an axial opening therein fitted on the end portion of the stem, cooperating means on the body and stem for limiting the depth to which the end portion of the stem may enter the body, the body having an annular neck portion thereon above the end of the stem, a marking disk portion on the body connected thereto by the annular neck portion, there being a cavity in the body above the stem surrounded by the neck portion and closed at the end of the marking disk portion, the marking disk portion being normally planar with printing characters on its exterior face, the marking disk portion and neck portions being of a resilient rubberous material whereby the printing surface may deform when pressed against a concave or convex surface, and means for venting the cavity to the atmosphere.

2. A device for printing as defined in claim 1 wherein the means for venting the cavity comprises a passage in the stem extending from the end thereof longitudinally of the stem and opening to atmosphere below the end of the cylindrical body of the marking die.

3. A device for printing as defined in claim 1 wherein the means for venting the cavity comprises a passage in the stem extending from the end thereof longitudinally of the stem and opening to atmosphere below the end of the cylindrical body of the marking die, said means on the stem for limiting the depth to which the stem may enter the body comprising an annular flange cooperating with the body, the marking die with the body, neck portion and marking disk portion being integral.

References Cited UNITED STATES PATENTS 921,224 5/1909 Frost 101-379 994,971 6/1911 Beck 101-379 X 1,048,281 12/1912 Bing 101-379 1,236,304 8/1917 Howell 101-379 1,238,229 8/1917 Weiler 101-35 1,271,826 7/1918 Anderson 101-379 X 1,334,822 3/1920 Varble 101-35 1,570,387 1/1926 Meyer 101-379 2,077,791 4/1937 H-akogi 101-35 2,201,302 5/1940 Rowe 101-41 X 2,232,410 2/1941 Smith 101-406 3,230,880 1/1966 Beaver 101-380 WILLIAM B. PENN, Primary Examiner. 

1. IN A DEVICE FOR PRINTING ON SPHERICALLY-CURVED CONVEX AND CONCAVE SURFACES, AN OPERATING STEM COMPRISING A ROD HAVING AN END PORTION TO RECEIVE A MARKING DIE, A MARKING DIE HAVING A CYLINDRICAL BODY WITH AN AXIAL OPENING THEREIN FITTED ON THE END PORTION OF THE STEM, COOPERATING MEANS ON THE BODY AND STEM FOR LIMITING THE DEPTH TO WHICH THE END PORTION OF THE STEM MAY ENTER THE BODY, THE BODY HAVING AN ANNULAR NECK PORTION THEREON ABOVE THE END OF THE STEM, A MARKING DISK PORTION ON THE BODY CONNECTED THERETO BY THE ANNULAR NECK PORTION, THERE BEING A CAVITY IN THE BODY ABOVE THE STEM SURROUNDED BY THE NECK PORTION AND CLOSED AT THE END OF THE MARKING DISK PORTION, THE MARKING DISK PORTION BEING NORMALLY PLANAR WITH PRINTING CHARACTERS ON ITS EXTERIOR FACE, THE MARKING DISK PORTION AN NECK PORTIONS BEING OF A RESILIENT RUBBEROUS MATERIAL WHEREBY THE PRINTING SURFACE MAY DEFORM WHEN PRESSED AGAINST A CONCAVE OR CONVEX SURFACE, AND MEANS FOR VENTING THE CAVITY TO THE ATMOSPHERE. 